Method for activating a self-contained biological indicator

ABSTRACT

The present invention provides a device for activating a self-contained biological indicator. The biological indicator includes a casing, an ampule having a growth-promoting medium disposed therein and microorganisms. The ampule and microorganisms are disposed within the casing. The device is comprised of a first lever arm having a cavity formed therein. The cavity is dimensioned to receive a biological indicator. A second lever arm has a protrusion extending from a surface thereof and is moveable relative to the first lever arm to deform a casing of the biological indicator thereby fracturing an ampule in the casing and exposing microorganisms in the casing to a growth-promoting medium in the ampule of the biological indicator.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/137,591, filed Jun. 12, 2008, now U.S. Pat. No. 8,173,418, which ishereby fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to self-contained biological indicatorsfor evaluating the efficacy of a sterilization process, and moreparticularly, to a device for activating a self-contained biologicalindicator.

BACKGROUND OF THE INVENTION

Sterilization is a process conducted in a specially designed chamber orsterilizer that results in a complete eradication of all viablemicroorganisms. Sterilization techniques have evolved over time from thetraditional methods employing saturated steam at elevated temperatureand ethylene oxide gases to more modem techniques, such as thoseemploying liquid, vapor and plasma. Regardless of the techniqueutilized, the effectiveness of the applied sterilization process must beevaluated especially when sterilizing instruments and devices invasiveto the human body.

Several methods are currently available for evaluating the effectivenessof a sterilization process. In some applications, chemical indicatorsare placed in the sterilization process to verify that the sterilizingmedium was present in the correct concentration during the sterilizationprocess. In other applications, process indicators are used to determineif the sterilizing medium was present in the correct concentration forthe proper amount of time. Still other applications use biologicalindicators to determine if the sterilizing medium was sufficient todeactivate a predetermined number of microorganisms on a test strip orcontained in the biological indicator.

The biological indicator is typically an absorbent paper strip thatcontains a predetermined number of microorganisms. The biologicalindicator is exposed to the sterilizing medium during the sterilizationprocess. At the conclusion of the sterilization process, the biologicalindicator is placed into a vial containing a growth-promoting medium,i.e., nutrients that aid in the growth of the microorganism. If thereare any viable microorganisms on the paper strip that survived thesterilization process, these microorganisms will grow and produce acolor change in the growth-promoting medium when properly incubated. Thesterilization process is determined to be successful if there is nocolor change in the growth-promoting medium. In one embodiment, thebiological indicator and the growth-promoting medium are disposed in acommon housing. The combination of biological indicator and thegrowth-promoting medium in a common housing is often called a“self-contained biological indicator” (SCBI).

Self-contained biological indicators are generally comprised of atubular housing having an open end and a closed end. A vial containing agrowth-promoting medium is disposed in the housing. A source ofmicroorganisms is also disposed in the housing. The source ofmicroorganisms is typically an absorbent paper strip that has beenimpregnated with a pre-determined concentration of viablemicroorganisms. The microorganisms may also be disposed directly on theexterior surface of the vial. A cap is disposed over the open end of thehousing. The cap is operable to move between an open position and aclosed position. When the cap is in the open position, the interior ofthe housing is in fluid communication with the environment. In thisrespect, a sterilizing medium is able to flow into the interior of thehousing and contact the source of microorganisms during thesterilization process. The self-contained biological indicator isremoved from the chamber of the sterilizer at the end of the process.The cap is then moved to a closed position wherein the interior of thehousing is fluidly isolated from the environment. Once sealed, thesource of microorganisms is exposed to the growth-promoting medium byfracturing or breaking the vial containing the growth-promoting medium.The SCBI is then incubated at a predetermined temperature for apredetermined duration. At the end of the incubation period, theindicator is evaluated either visually or with a detector to determinewhether any microorganisms survived the sterilization process.

As described above, the source of microorganisms is exposed to thegrowth-promoting medium. In order to expose the source of microorganismsto the growth-promoting medium, the vial must be fractured by the user.Presently, the user must exert a significant amount of force to thehousing of the biological indicator to fracture the vial disposetherein. In some instances, the user may use a blunt instrument, e.g., ahammer, to fracture the vial. As a result, significant damage may occurto the biological indicator if excessive force is used. In this respect,present devices are complicated and may require multiple operations toseal and activate the biological indicator.

The present invention provides a device wherein a self-containedbiological indicator for determining the efficacy of a sterilizationprocess can be activated.

SUMMARY OF THE INVENTION

In accordance with a preferred embodiment of the present invention,there is provided a device for activating a self-contained biologicalindicator. The biological indicator includes a casing, an ampule havinga growth-promoting medium disposed therein and microorganisms. Theampule and microorganisms are disposed within the casing. The device iscomprised of a first lever arm having a cavity formed therein. Thecavity is dimensioned to receive a biological indicator. A second leverarm has a protrusion extending from a surface thereof and is moveablerelative to the first lever arm to deform a casing of the biologicalindicator thereby fracturing an ampule within the casing and exposingmicroorganisms within the casing to a growth-promoting medium disposedin the ampule.

In accordance with yet another embodiment of the present invention,there is provided a method of activating a self-contained biologicalindicator in a device. The biological indicator includes a casing, anampule having a growth-promoting medium disposed therein andmicroorganisms. The ampule and microorganisms are disposed within thecasing. The method is comprised of the steps of:

a) moving a device comprised of a first lever arm and a second lever armto an open position, wherein the first lever arm is moveable relative tothe second lever arm;

b) locating a biological indicator in a cavity located in the firstlever arm of the device while the device is in the open position; and

c) moving the device to a closed position by moving the second lever armrelative to the first lever arm such that a protrusion on the secondlever arm fractures an ampule within the biological indicator therebyallowing a growth-promoting medium within the ampule to be exposed tomicroorganisms disposed in a casing of the biological indicator.

An advantage of the present invention is the provision of a device foractivating a biological indicator.

Another advantage of the present invention is the provision of a devicethat seals a self-contained biological indicator prior to activating theself-contained biological indicator.

Still another advantage of the present invention is the provision of adevice, as described above, that requires a simple operation to seal andactivate a self-contained biological indicator.

Still another advantage of the present invention is the provision of adevice, as described above, that is inexpensive to manufacture.

Yet another advantage of the present invention is the provision of adevice, as described above, that allows hand-held operation.

Yet another advantage of the present invention is the provision of adevice, as described above, that can be operated with one hand.

These and other advantages will become apparent from the followingdescription of a preferred embodiment taken together with theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangement ofparts, a preferred embodiment of which will be described in detail inthe specification and illustrated in the accompanying drawings whichform a part hereof, and wherein:

FIG. 1 is a perspective view of a device for sealing and activating aself-contained biological indicator according to an embodiment of thepresent invention, wherein the device is shown in an open position witha biological indicator located outside the device;

FIG. 2 is a side plan view of the device and biological indicator shownin FIG. 1;

FIG. 3 is a top plan view of the biological indicator shown in FIG. 2,wherein the biological indicator is shown in phantom inside the device;

FIG. 4 is a side plan view partially in section of the device forsealing and activating a biological indicator, wherein the device isshown in a partially open position with a biological indicator locatedinside the device;

FIG. 5 is a side plan view partially in section of the device shown inFIG. 4, wherein the device is shown in a closed position;

FIG. 6 is a sectional view taken along lines 6-6 of FIG. 3;

FIG. 7 is a sectional view of a biological indicator showing a cap ofthe biological indicator in an unsealed or open position; and

FIG. 8 is a sectional view of the biological indicator shown in FIG. 7,showing the cap of the biological indicator in a sealed or closedposition.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawings wherein the showings are for the purposeof illustrating an embodiment of the invention only, and not for thepurpose of limiting same. FIGS. 7 and 8 show a typical self-containedbiological indicator 50 that is used in connection with device 10.Broadly stated, biological indicator 50 is comprised of a casing 52, acap 72, an ampule 66 and a microorganism-inoculated element 68. Itshould be understood that indicator 50 is merely exemplary of abiological indicator suitable for use in connection with the presentinvention, and is not intended to limit the scope of the presentinvention.

Casing 52 is a generally cylindrical container having a cylindrical sidewall 54, an open end 56 and a closed end 58. Casing 52 defines aninterior cavity 62 dimensioned to receive ampule 66 andmicroorganism-inoculated element 68. A series of tabs 64 extend radiallyoutward from side wall 54 near open end 56. The material for casing 52is chosen such that when side wall 54 of casing 52 is subjected to aforce, side wall 54 will deform but not fracture. Casing 52 ispreferably formed of a translucent, polymer material, such as by way ofexample and not limitation, polypropylene, polyethylene, polycarbonate,polyvinyl carbonate, polyvinyl styrene, polyvinyl acetate,polymethylmethacrylate or any copolymers of the above materials.

Ampule 66 is a sealed enclosure formed from a frangible material, suchas glass or other suitable materials, that allows ampule 66 to be openedby applying an external force sufficient to fracture or break ampule 66,as shall be described in greater detail below. It shall be appreciatedthat ampule 66 may assume shapes that differ from the shape illustratedherein. A growth-promoting medium 88 is disposed within ampule 66.Growth-promoting medium 88 is well known to those skilled in the art,and therefore shall not be described in detail. Examples of commonlyused growth-promoting mediums include, but are not limited to, trypicsoy broth and soybean casein digest growth media.

In the illustrated embodiment, microorganism-inoculated element 68 is apaper patch inoculated with spores or other microorganisms, as isconventionally known in the art. Microorganism-inoculated element 68 maybe attached to the inner surface of casing 52, but in the embodimentshown, element 68 is affixed to an outer surface of ampule 66. In analternative embodiment (not shown), the microorganisms are disposeddirectly on the exterior surface of ampule 66 or on the interior surfaceof casing 52.

Cap 72 is generally cup-shaped and includes a cylindrical side wall 74and an end wall 76. A ring-shaped boss 82 extends inward from end wall76. Boss 82 is centrally located on cap 72. An annular protrusion 84extends radially outward from boss 82 near a distal end thereof. Anannular groove 78 is formed in side wall 74 near an open end of cap 72.Annular groove 78 is dimensioned to accept tabs 64 of casing 52, as bestseen in FIG. 7. An opening 86 is formed between casing 52 and cap 72, asbest seen in FIG. 7, when tabs 64 are disposed in groove 78.

Cap 72 is movable between an unsealed or open position, best seen inFIG. 7, and a sealed or closed position, best seen in FIG. 8. In theopen position, tabs 64 of casing 52 are disposed in annular groove 78 ofcap 72. In this respect cavity 62 of casing 52 is in fluid communicationwith the exterior of indicator 50 through opening 86. In the sealedposition, boss 82 of cap 72 is disposed in open end 56 of casing 52 suchthat annular protrusion 84 sealingly engages side wall 54 of casing 52.In this respect, a seal is formed between cap 72 and casing 52, therebyisolating cavity 62 from the exterior of indicator 50.

FIG. 1 shows a device 10 for activating a self-contained biologicalindicator (such as indicator 50 described above) in accordance with anembodiment of the present invention. Device 10 is described herein inconnection with the sealing and activation of indicator 50. However, itis contemplated that device 10 may be used to seal and activatebiological indicators of alternative designs.

Broadly stated, device 10 is comprised of a first lever arm 20 and asecond lever arm 40. In the illustrated embodiment, a hinge member 30connects a distal end of first lever arm 20 to a distal end of secondlever arm 40 such that second lever arm 40 is rotatable relative tofirst lever arm 20. Second lever arm 40 is rotatable such that device 10is movable between an open position and a closed position, as shall bedescribed in greater detail below. It will be appreciated that firstlever arm 20 and second lever arm 40 may be connected with each other bymeans other than hinge member 30. For example, first lever arm 20 andsecond lever arm 40 may be molded such that an integral hinge is formedtherebetween.

In the embodiment shown, first lever arm 20 is an elongated rectangularmember with a top surface 22. A cavity 28 is formed in top surface 22,as best seen in FIG. 1. Cavity 28 is defined by end surface 32, sidewalls 34, 36 and bottom surface 37. Cavity 28 is dimensioned to accept abiological indicator, such as indicator 50 described above. In theillustrated embodiment, a recess 38 is formed proximate one end ofcavity 28, as best seen in FIG. 1. Recess 38 is dimensioned tofacilitate the removal of indicator 50 from cavity 28, as shall bedescribed in greater detail below.

In the embodiment shown, second lever arm 40 is a generally L-shapedmember having an elongated first portion 42 and a shorter second portion44 that is substantially perpendicular to first portion 42. A protrusion46 extends from first portion 42, as shown in FIG. 1. In the embodimentshown, protrusion 46 is a generally triangular-shaped member thatextends outward from first portion 42. Protrusion 46 is located alongfirst portion 42 such that protrusion 46 aligns with cavity 28 whendevice 10 is in the closed position.

A cam member 48 is disposed at a corner where first portion 42 meetssecond portion 44. In the embodiment shown, cam member 48 is a generallyrectangular element that extends outwardly from first portion 42 andsecond portion 44. An engaging surface or edge 48 a of cam member 48faces cavity 28.

Device 10 is operable to be moved between the open position, best seenin FIGS. 1 and 2, and the closed position, best seen in FIG. 5. In theopen position, first lever arm 20 and second lever arm 40 are disposedsuch that cavity 28 in first lever arm 20 is accessible. In the closedposition, edge 48 a of cam member 48 is partially disposed in cavity 28of first lever arm 20 and protrusion 46 aligns with and extends intocavity 28, as best seen in FIG. 5. In the embodiment shown, first leverarm 20 and second lever arm 40 are substantially parallel when device 10is in the closed position.

Operation of device 10 will now be described in connection with thesealing and activation of a biological indicator (such as indicator 50).Indicator 50 is sealed and activated using device 10 following the useof indicator 50 in a sterilizer. In this respect, indicator 50 is placedwithin a chamber of a sterilizer (not shown) along with objects to besterilized. Cap 72 of indicator 50 is in the unsealed or open position,as illustrated in FIG. 7. During a sterilization cycle, the sterilantfluid (gas or liquid) that is used in the sterilizer flows throughopening 86 between cap 72 and casing 52, and into cavity 62 of casing 52where the sterilant fluid acts on the microorganism-inoculated element68.

At the end of the sterilization cycle, indicator 50 is removed from thechamber of the sterilizer. Device 10 is moved to the open position byrotating second lever arm 40 away from first lever arm 20. Indicator 50is then placed into cavity 28 of device 10, as shown in FIGS. 2, 3 and6. As described above, cavity 28 of device 10 is dimensioned such thatwhen indicator 50 is disposed in cavity 28, indicator 50 contacts endsurface 32 of cavity 28, as best seen in FIG. 4. Device 10 is moved fromthe open position to the closed position by rotating second lever arm 40toward first lever arm 20. As second lever arm 40 moves toward firstlever arm 20, device 10 moves from the open position, to an intermediateposition to a closed position. As device 10 moves from the open positionto the intermediate position, edge 48 a of cam member 48 moves intocavity 28. Accordingly, indicator 50 is captured between cam member 48and end surface 32. Edge 48 a of cam member 48 initially contacts orengages cap 72 of indicator 50 as first lever arm 20 and second leverarm 40 move towards each other. As second lever arm 40 continues to movetoward first lever arm 20, the distance between edge 48 a of cam member48 and end surface 32 decreases thereby causing the distance between cap72 of indicator 50 and closed end 58 of indicator 50 to decrease. As cap72 moves toward closed end 58, a first compressive force is applied toindicator 50 thereby causing cap 72 of indicator 50 to move from theunsealed or open position, best seen in FIG. 7, to the sealed or closedposition, best seen in FIG. 8. Device 10 is in the intermediate positiononce cap 72 is in the sealed or closed position. In other words, cammember 48 is dimensioned such that when device 10 is in the intermediateposition, the distance between engaging surface or edge 48 a of cammember 48 and end surface 32 is equal to or less than the height ofself-contained biological indicator 50 in the sealed or closed position.As a result, indicator 50 is sealed by device 10 when device 10 is inthe intermediate position.

As second lever arm 40 continues to move relative to first lever arm 20,device 10 moves from the intermediate position to the closed position.As device 10 moves from the intermediate position to the closedposition, protrusion 46 moves toward cavity 28 in first lever arm 20.Protrusion 46 initially contacts side wall 54 of casing 52. As secondlever arm 40 continues to move toward first lever arm 20, protrusion 46exerts a second, compressive force on side wall 54 of casing 52.Protrusion 46 is dimensioned such that the second, compressive forceexerted on side wall 54 of casing 52 causes side wall 54 to deform andapply a compressive force to ampule 66 sufficient to fracture or breakampule 66, as shown in FIG. 5. Device 10 is in the closed position whenampule 66 is fractured by protrusion 46. As a result,microorganism-inoculated element 68 is exposed to growth-promotingmedium 88 within ampule 66.

The sealing of casing 52 and fracturing of ampule 66 basically“activates” indicator 50 by exposing microorganism-inoculated element 68to medium 88. Once activated, device 10 is moved to the open positionand indicator 50 is removed from device 10. Recess 32 is dimensioned toallow an operator's finger to grip closed end 58 of indicator 50. Inthis respect, recess 32 is dimensioned to allow an operator to squeezeclosed end 58 and cap 72 between a thumb and an opposing finger to aidin the removal of indicator 50 from device 10. Indicator 50 is thenplaced in a conventional incubator (not shown) at a temperature and fora time suitable for growing the microorganism in growth-promoting medium88.

The present invention thus provides a device for quickly and easilyactivating a self-contained biological indicator 50. As indicated above,the rotation of second lever arm 40 relative to first lever arm 20 firstseals the self-contained biological indicator 50 then fractures ampule66 disposed in casing 52.

In an alternative embodiment of the present invention (not shown), cammember 48 is omitted from device 10. In this embodiment, it iscontemplated that a user manually seals indicator 50 prior to placingindicator 50 in device 10. Thereafter, device 10 is moved from an openposition to a closed position to fracture ampule 66, thereby activatingindicator 50. Once activated, device 10 is moved to the open positionand indicator 50 is removed from device 10.

The foregoing description is a specific embodiment of the presentinvention. It should be appreciated that this embodiment is describedfor purposes of illustration only, and that numerous alterations andmodifications may be practiced by those skilled in the art withoutdeparting from the spirit and scope of the invention. It is intendedthat all such modifications and alterations be included insofar as theycome within the scope of the invention as claimed or the equivalentsthereof.

Having described the invention, the following is claimed:
 1. A method ofactivating a self-contained biological indicator using a device having afirst lever arm and a second lever arm wherein a cavity is formed insaid first lever arm and said first lever arm is movable relative tosaid second lever arm, said biological indicator including a casing anda cap disposed on said casing, said cap movable between an open positionand a sealed position relative to said casing and said casing definingan interior cavity dimensioned to receive microorganisms and an ampulehaving a growth-promoting medium disposed therein, said methodcomprising the steps of: a) moving said device to an open positionwherein said cavity of said first lever arm is accessible; b) locating abiological indicator in said cavity of said first lever arm while saiddevice is in said open position; and c) moving said device to a closedposition to activate said biological indicator, wherein said secondlever arm of said device is moved relative to said first lever arm, saidstep of moving said device to said closed position includes: 1) applyinga compressive force to said cap of said biological indicator located insaid cavity of said first lever arm to move said cap to said sealedposition; and 2) after said cap is in said sealed position, deformingsaid casing of said biological indicator thereby fracturing said ampulewithin said casing to expose said microorganisms within said interiorcavity of said casing to said growth promoting medium in said ampule. 2.A method as defined in claim 1, further comprising the steps of: d)moving said second lever arm relative to said first lever arm such thatsaid device is in said open position and said cavity of said first leverarm is accessible; and e) removing said biological indicator from saidcavity of said first lever arm.
 3. A method as defined in claim 1,wherein said first lever arm and said second lever arm are movablerelative to each other using one hand.
 4. A method as defined in claim1, wherein an end of said first lever arm is hinged to an end of saidsecond lever arm for moving said second lever arm relative to said firstlever arm.
 5. A method as defined in claim 1, wherein during said stepc) of moving said device to said closed position an engaging edge ofsaid second lever arm applies said compressive force to said cap of saidbiological indicator to move said cap to said sealed position.
 6. Amethod as defined in claim 5, wherein during said step c) of moving saiddevice to said closed position said engaging edge of said second leverarm moves toward an end wall of said cavity of said first lever arm. 7.A method as defined in claim 1, wherein during said step c) of movingsaid device to said closed position a protrusion formed on said secondlever arm contacts said casing of said biological indicator to deformsaid casing.
 8. A method as defined in claim 7, wherein during said stepc) of moving said device to said closed position said protrusion movesin a direction substantially perpendicular to a bottom wall of saidcavity of said first lever arm.